Drinnok

Drinnok is a former antagonist, a powerful megalodon revealed in book five and the King of Fifth Shiver. Drinnok appears to be the biggest and most dangerous antagonist yet in Books 4 and 5 but Gray notices something different in him than the other evil sharks. His shiver is named Fifth Shiver, which was destroyed by Grimkahn, Hokuu, and Sixth Shiver.

Drinnok appears as the main antagonist for the first half of the book. He is disgusted with Hokuu for failing to bring him and his minions out of the Dark Blue. Then a large plesiosaur from Grimkahn's group challenges him to a fight, calling him a fool. In the fight, Drinnok bites off the poor plesiosaur's head. Eventually, Drinnok escapes from the Underwaters and encounters Gray. Gray tries to reason with him but it fails when AuzyAuzy ambushes and attacks Fifth Shiver without Gray's command, enraging the King. Later, Gray finds out that Drinnok wasn't truly responsible for the death of King Bollagan and his line. It was Hokuu and Grimkahn. Next, Barkley talks with him and convinces him to meet with Gray, and that it's not a trick. Drinnok and Gray have a meeting. In the end, Drinnok agrees that peace would be worth a try. Hokuu and Grimkahn then attack Fifth Shiver. Drinnok and his allies fight back but are beaten off. Drinnok is fatally injured by one of Hokuu's dark-kata blasts and tells Gray to go before he dies. Grimkahn then eats his body and proclaims that Fifth Shiver is dead, and establishes himself as the new leader of Sixth Shiver.